Embodiments of the invention relate to switching environments, and in particular, switch mode transition and processing upon loss of controller communication.
OpenFlow switches are based on an Ethernet switch with an internal flow table, and a standardized interface to add and remove flow entries. Ethernet switches and routers may contain flow tables (typically built from ternary content-addressable memory (TCAM)) that run at line-rate to implement firewalls, network address translation (NAT), quality of service (QoS), and to collect statistics.
In OpenFlow, upon loss of communication with a controller, packets that cannot match any flow entries will be dropped. The packet drop continues to worsen as flow entries might become invalid due to timing out, or all the exiting flow entries may become invalidated immediately, which cause packets to become flooded during transition.